Treesearch

This guide was prepared to assist field foresters in the use of stress wave timing instruments to locate and define areas of decay in standing timber. The first three sections provide background information, the principles of stress wave nondestructive testing, and measurement techniques for stress wave nondestructive testing. The last section is a detailed description of how to apply stress wave nondestructive testing methods to standing timber. A sample field data acquisition form is included.

Piloted ignition behavior of materials, particularly wood products, during transitions between heating regimes is measured and modeled in a cone calorimetry (ISO 5660) heating environment. These include (1) effect of material thickness, density, moisture content, and paint coating variations on thermal response characteristics, (2) effect of fire retardant treatment concentration on smoldering and flashing prior to flaming ignition, and (3) effect of cone irradiance on inducing convective heat loss of the material. Thermophysical properties of volumetric heat capacity or thermal conductivit...

Existing log grading procedures in the United States make only visual assessments of log quality. These procedures do not incorporate estimates of the modulus of elasticity (MOE) of logs. It is questionable whether the visual grading procedures currently used for logs adequately assess the potential quality of structural products manufactured from them, especially those for which MOE is of primary concern. The purpose of this study was to investigate the use of stress wave nondestructive evaluation techniques to sort red maple logs for the potential quality of lumber obtained from them....

Fire resistance data on exposed wood beams and columns are plentiful, but few studies have been done on exposed wood members in tension and in decks. To provide data to verify the application of a new calculation procedure, a limited series of fire resistance tests were conducted on wood members loaded in tension and on exposed wood decks.

Preservative treated wood contains components that may be toxic to non-target organisms if released into the environment in sufficient quantities. Numerous studies have been conducted to determine the rate of preservative release from treated wood and/or the extent of their subsequent accumulation in the environment. These studies have produced a wide range of results with a corresponding range of interpretations and recommendations. This paper reviews research on wood preservative leaching and environmental accumulation and discusses sources of the variability in research findings....

For decades chromated copper arsenate (CCA) was the primary preservative for treated wood used in residential construction. However, recent label changes submitted by CCA registrants will withdraw CCA from most residential applications. This action has increased interest in arsenic-free preservative systems that have been standardized by the American Wood Preservers’ Association. These include acid copper chromate (ACC), alkaline copper quat (ACQ), copper azole (CBA-A and CA-B), copper citrate (CC), copper dimethyldithiocarbamate (CDDC), and copper HDO (CX-A). All of these CCA alternatives...

The purpose of this study was to clarify the effects of composite processing and moisture sorption on laboratory fungal resistance of wood-plastic composites. A 2-week water soaking or cyclic boiling-drying procedure was used to infuse moisture into composites made from high-density polyethylene filled with 50 percent wood flour and processed by extrusion, compression molding, or injection molding. Extruded composites absorbed the most moisture; compression-molded composites absorbed less than did extruded composites, and injection-molded composites absorbed the least. Although more...

Bioprocessing CCA wood waste is an efficient and economical alternative to depositing the waste in landfills, especially if landfill restrictions on CCA waste are imposed nation wide. We have developed bioremediation and degradation technologies for microbial processing of CCA waste. The technologies are based on specially formulated inoculum of wood decay fungi, obtained through strain selection to obtain metal tolerant fungi. Two strains of Meruliporia incrassata and two strains of Antrodia radiculosa were selected for capacity to degrade CCA wood, thereby reducing the waste volume....

Mushroom-producing white-rot fungi can be used to convert woodwaste into gourmet and medicinal mushrooms. White-rot fungi do not always readily colonize on conifer wood because of its extractives content. This study evaluated the resinous extractive content of loblolly pine (Pinus taeda), ponderosa pine (Pinus ponderosa), and an unknown species of southern yellow pine before and after treatment with the extractive-degrading fungi Aureobasidium spp., Ceratocystis spp., and Ophiostoma spp. Fungal treatment removed 70 to 99.9 percent of extractives. Scanning electron microscopy showed heavy...

Southern yellow pine sapwood stakes and blocks were treated with the sodium salt of the calcium-precipitating compound N’N-hydroxynapthalimide (NHA) and leach tested for 2 weeks using the American Wood-Preservers’ Association (AWPA) standard. Leacheates were measured for NHA using a microplate optical density ultraviolet reader, and leach rates were estimated for tap water, distilled water, and seawater. The percentage of NHA lost from blocks ranged from a low of 5.0 percent for seawater to 26.4 percent for distilled water. Clearly, higher inorganic ion concentrations in the leaching...